The present invention relates to a system for the alignment of products.
The present invention can be used to good advantage in the food packaging industry, in particular for the packaging of biscuits, chocolates and similar products which do not have any surface that is flat enough to allow them to assume a stable transfer position. The description which follows refers to this particular field of application but without thereby restricting the scope of the inventive concept.
Usually, the food products feed out of the production machines on a conveyor arranged in ordered lines parallel to the direction of feed of the conveyor itself and normally side by side in such a manner as to form ordered rows crossways with respect to said direction of feed.
If the shape of the food products is like that described above, it is practically impossible to arrange them on the conveyor in the manner described above and to maintain the arrangement. Therefore, products that are shaped in such a manner that they cannot maintain a stable transfer position, for example, those with polyhedral or substantially spherical or ovoid shapes, must be placed in specially made hollows, side by side in such a way as to form ordered rows. These hollows can be made directly in the conveyor or in trays which are in turn placed on the conveyor.
The conveyor is normally driven intermittently and feeds the products to an alignment device constituting an infeed device to a second conveyor, also driven intermittently, which in turn feeds a user unit normally consisting of a line for the packaging of the products themselves. When the products reach the alignment device, they stop for a defined length of time required by the alignment device itself to arrange them in a single line where previously they were arranged in two or more lines parallel to the feed direction of the conveyor.
The disadvantage of the method just described is due to the intermittent feed motion of the conveyors and, hence, the relatively low speed at which the alignment device can rearrange the products while transferring them from one conveyor to the other.
Up to the present time, use has been made of devices designed to align rectangular food products, as described in U.S. Pat. No. 5,381,884 which can be referred to for a complete description. Devices of this kind are used to pick up rectangular products, having substantially parallelepipedal shapes, from a first feed conveyor and to transfer them to a second conveyor in any position relative to the carrying surface of the second conveyor. In practice, the products can be dropped onto the second conveyor in any position.
Devices of this kind, however, have the disadvantage of being unsuitable for products whose shapes make them unstable during transfer. This is because it is difficult to achieve the precision required to drop each product exactly into the corresponding hollow made in the receiving conveyor and designed to keep it in the right position while it is being transferred.
The aim of the present invention is to provide a method to align products whose shapes make them unsuitable for stable transfer and which overcomes the disadvantages described above.